The present invention relates to a pest repellent composition, and more particularly to such compositions containing carane-3,4-diol as an active ingredient therein.
Convenient pest repellents have been developed as pest thwarting compositions, which compositions are either utilized by directly spraying or spreading onto the human body. U.S. Pat. No. 5,130,136, which is incorporated herein by reference in its entirety, discloses carane-3,4-diol as an effective active ingredient for pest repellents, but pest repellents containing carane-3,4-diol have several deficiencies despite the ability of carane-3,4-diol to efficiently repel pests. One of said deficiencies lies with the adhesive character of carane-3,4-diol. Specifically, the adhesive character of carane-3,4-diol often causes a viscid sensation similar to the feeling of having a film of sweat covering the body (hereinafter referred to as an xe2x80x9cadhesive feelingxe2x80x9d) when a pest repellent which contains carane-3,4-diol is applied to the body. Because such an adhesive feeling is undesirable, pest repellents comprising inorganic or organic powders have been proposed to lessen the adhesive feelings associated with carane-3,4-diol pest repellent compositions. However, when such pest repellent compositions comprising powders are applied to the body, they often produce the visually unappealing effect of having a white powder sprinkled onto the applied surface (hereinafter referred to as a xe2x80x9cwhiteningxe2x80x9d effect).
The convenience with which such a pest repellent can be used is additionally diminished when the pest repellent comprises a powder. For example, when utilized in a spraying device, powders within a spray or aerosol composition can often cause obstructions inside pumps, valves, tubes, and/or at the nozzle of an atomizer, so that the spraying device cannot dispense the pest repellent composition efficiently. Further, because powders within the aerosol composition of the pest repellent composition can also tend to settle at the bottom of the spraying device, difficulties are also encountered in evenly redistributing powders after the they have settled at the bottom of the device.
The above deficiencies that are associated with prior known pest repellents are problematic. The above deficiencies are also especially troublesome in that such pest repellents can be inconvenient to utilize, whereas spraying devices are typically known and relied upon for their ease of use. Accordingly, the present invention is concerned with providing an effective pest repellent composition that can overcome the prior encountered problems in the art of adhesive feeling, whitening, and inconvenience.
The present invention provides for a pest repellent composition that may be formulated as an aerosol composition or as a liquid composition. More particularly, the present invention provides for aerosol and liquid pest repellent compositions that comprise a non-porous round polyethylene powder, a solvent, and carane-3,4-diol as a pest repelling active ingredient. The provided aerosol compositions additionally contain a propellant. The inventive composition overcome the prior encountered problems of adhesive feeling, whitening, and at the same time are convenient to utilize. For example, the present inventive compositions allow for spraying to be performed smoothly without encountering any problems of adhesive feeling, whitening or clogging of the spray or aerosol apparatus with which they are applied to a body surface.
The pest repellent composition of the present invention may be formulated as a liquid composition or as an aerosol composition that contains said liquid composition in combination with a propellant, to thereby repel objective pests. Examples of the objective pests that can be repelled with the inventive compositions are the blood-sucking insects/acarina such as mosquitoes (Culicidae), black flies (Simuliidae), stable flies (Stomoxyidae), sand flies, biting midges (Ceratopogonidae), and the like.
The pest repellent compositions of the present invention contain carane-3,4-diol, which is a highly effective but oily and highly adhesive active ingredient. In the case that the pest repellent composition of the present invention is in the form of a liquid, the liquid preferably comprises carane-3,4-diol in an amount of about 3% to 50% by weight, more preferably about 4% to 45% by weight, and most preferably about 5% to 40% by weight, based on the total weight of the liquid composition.
The solvent employed in the liquid compositions of the instant invention preferably contains paraffin (or isoparaffin) and alcohol, but is not limited thereto, since other conventional solvents are also well known to those skilled in the art.
Preferably, the liquid compositions of the present invention comprise as a solvent, paraffin (or isoparaffin) in an amount of about 3% to 30% by weight, more preferably about 5% to 25% by weight, and an alcohol at an amount of about 20% to 90% by weight, preferably about 50% to 85% by weight, based on the total weight of the liquid composition.
The term xe2x80x9cparaffinxe2x80x9d as used herein means a saturated aliphatic hydrocarbon having the formula CnH2n+2, and includes straight chain paraffins (i.e. normal-paraffin) and branched chain paraffins (i.e. isoparaffin). As such, either normal-paraffins or isoparaffins may be employed as a solvent ingredient in the inventive compositions. Isoparaffin is preferably used as an ingredient in the solvent of the present inventive compositions. The carbon number of the employed paraffin or isoparaffin is preferably 4 to 20, and more preferably 4 to 15. Furthermore, the selected solvent may contain a mixture of miscellaneous paraffins, if so defined. For example, commercially available isoparaffins that may be employed as a solvent or a solvent ingredient in the present invention include IP Solvent, IP-1016, IP-1620, IP-2028 (product names from Idemitsu Petrochemical Company Ltd.), Isopar E, Isopar G, Isopar H (product names from Exxon Chemical Company), and so on.
The solvent used to produce one of the inventive compositions should preferably also comprise an alcohol such as a C1-8 lower alcohol, but the use of an alcohol is not mandatory in the present invention. Preferably, the chosen alcohol should possess the ability to fulfill cosmetic purposes. Accordingly, examples of alcohols that are useful as solvents in the present invention are ethyl alcohol, isopropyl alcohol, other C1-8 lower alcohols and alcohols that have been denatured with perfumes such as ethanols denatured with Bitrex (Denatonium benzoate, Mac Pharen Smith Ltd.). Further, a mixture of such alcohols can also be used in the present invention, if so desired.
The non-porous round polyethylene powders, which may be employed in the inventive compositions, preferably contain copolymers comprising mainly ethylene units, such as an ethylenepropylene copolymer. However, other copolymers containing ethylene units may also be utilized in the invention, provided that their powders are round and non-porous. The particles of any such powders used in the inventive compositions should preferably have the dimensions of a generally spherical shape, and more preferably have an average diameter of about 5 xcexcm to 30 xcexcm, and more preferably of about 7 xcexcm to 20 xcexcm. The present invention preferably comprises the non-porous round polyethylene powder particles in an amount where the weight ratio between carane-3,4-diol and the non-porous round polyethylene powder particles is from about 1:0.05 to 1:1, preferably from about 1:0.1 to 1:0.6, on a weight to weight basis.
In addition, the inventive liquid compositions, in order to more effectively distribute powder in the solvent, may optionally contain a dispersing agent. Various surfactants may be utilized as the dispersing agent, with examples of such surfactants including sorbitan fatty acid ester sufactants such as sorbitan monooleate and sorbitan monolaurate, silicone-type surfactants such as a copolymer of dimethylsiloxane and methyl(polyoxyethylene)siloxane as well as a copolymer of dimethylsiloxane and methyl(polyoxyethylene-polyoxypropylene)siloxane, mixtures thereof, and the like. It is more preferable to incorporate silicone-type surfactants in the inventive liquid compositions, since silicone-type surfactants have the ability to noticably lessen the adhesive feeling of the pest repellent composition. When present, the amount of the dispersing agent within one of the inventive liquid compositions is preferably about 5.0% by weight or less, and more preferably about 3.0% by weight or less, based on the total weight of the liquid composition.
In the case that the liquid pest repellent composition is formulated into an aerosol, the inventive aerosol should comprise a propellant in combination with a liquid composition of the present invention. Examples of suitable propellants that may be employed to prepare an aerosol include liquefied petroleum gas, propane, propylene, n-butane, isobutane, n-pentane, isopentane, dimethyl ether, carbon dioxide, compressed gases such as nitrogen gas, a mixture thereof, and the like. The propellant may be incorporated in the inventive compositions in an amount so that the ratio of weight of the liquid composition to the propellant is preferably from about 9:1 to 2:8, and more preferably from about 8:2 to 3:7, on a weight to weight basis.
Additionally, a preferable spraying system for an aerosol of the present invention is to utilize a device having a spray opening of a spraying button of about 0.4 mm to 1.1 mm, an inner diameter of a stem orifice of about 0.4 mm to 0.7 mm, a vapor tap orifice of about 0.5 mm to 0.7 mm, and an inner diameter of a dip tube of about 1 mm to 1.6 mm.
Preparation of one of the inventive liquid pest repellent compositions can be achieved by simply mixing each of the ingredients together, but a mixing method, wherein a shaking or stirring step is employed, may also be advantageously used to promote re-dispersibility of the prepared liquid or aerosol pest repellent. Moreover, while mixing of the liquid pest repellent composition may be performed by any suitable means (e.g. a high speed stirrer such as a homogenizer), it is preferable to utilize a device wherein ultrasonic waves are emitted (e.g. ultrasonic emitter) to obtain an even distribution of the powder within the liquid. Further, an aerosol of the present invention may be prepared by dispersing the non-porous round polyethylene powder in the liquid composition, before the propellant and the liquid composition are packed into an aerosol container, but it is also possible to load each ingredient of the liquid composition and the propellant into an aerosol container and subsequently disperse the powder by the use of a device such as an ultrasonic emitter. The time necessary to sufficiently distribute the non-porous round polyethylene powder in one of the inventive liquid or aerosol compositions differs upon the amount of pest repellent ingredient employed and the ratio between the amount of each ingredient in the inventive liquid or aerosol composition, but usually for about 2 to 10 minutes, and preferably about 3 to 7 minutes is necessary when the ultrasonic emitter is utilized at the frequencies of about 20 to 150 kHz, and the size of the composition is from about 50 mL to 150 mL.
A pest repellent composition of the present invention may also comprise as optional ingredients, fragrances, fungicides, coloring agents, humidity control agents, ultaviolet light absorbers, anti-oxidents and the like, if so desired, provided that the pest repellent composition still repels pests, does not provide whitening or adhesive feeling and remains convenient to utilize.